When installing my recently purchased head unit I noticed during testing that the instrument cluster was going haywire and that the warning chimes and lights kept flashing. I thought to unplug the OBD adapter (supplied on main harness) from the car and everything went back to normal. I figured I would reflash the Alp-RR and yet again it happened. Im flashing ALP-RR(SR)-FOR01-DS3 but should it be PF-FOR01-DS?

This is a normal reaction from the truck when something is connected to the OBD2, but doesn't have a good connection. It is likely that the pins inside the two plugs aren't making solid contact. At that point, I recommend hardwiring your OBD2 wires directly to the OEM side of the wiring. A solid wire to wire connection will ensure the issue goes away.

You were very close, it turned out to be that the Alpine harness was wired incorrectly (they reversed pin 6 and pin 14) so a quick swap and I was good to go. Hopefully this will help others you may have the same issue.